Drive arrangement for mower-conditioner equipped with a rotary disc cutter bar

ABSTRACT

A mower-conditioner includes a header or platform which is equipped with a rotary disc cutter bar having a relatively long length with at least two cutting units being outboard of a central discharge passage where a pair of conditioner rolls are mounted for receiving the cut crop. Aiding in conveying crop to the discharge passage are right- and left-hand sets of three crop converging drums provided at each side of the discharge passage. The outer drums of the two sets are respectively mounted to the top of the right- and left-hand end cutting units of the cutter bar while the other two drums on each side are located behind an inward and rearward extending line that is tangent to the cylindrical path traced by the outer and inner ones of the drums on each side of the discharge passage. In one embodiment, a direct drive transmission is provided, and in a second embodiment a hydraulic motor is provided, for driving the inner two converging drums of each set.

[0001] The present invention relates to a crop converging arrangementfor mower-conditioners, and more specifically relates to crop convergingarrangement associated with a rotary cutter bar of a mower-conditioner.

BACKGROUND OF THE INVENTION

[0002] U.S. Pat. No. 5,842,330, granted Dec. 1, 1998, discloses amower-conditioner equipped with a rotary cutter bar that includes a pairof converging drum at each of its opposite ends, with each pair of drumscooperating with a converging shield structure to converge cut crop to anarrower stream that is fed to the rear into a conditioning arrangement.This type of converging structure does not satisfactorily converge crop,especially when used with a longer cutter bar for cutting a wider swathof crop.

[0003] U.S. Pat. No. 5,433,064, granted Jul. 18, 1995, discloses amower-conditioner equipped with a rotary cutter bar that is relativelylong and includes a pair of driven converging drums arranged above thetwo outermost cutting units at each end of the cutter bar and usedtogether with a driven converging element located between them. The pairof converging drums and intermediate converging element are all locatedin line with the centers of rotation of the cutting discs and in thisposition are found to cause the cut crop transported by them to theconditioner to interfere with the uncut crop so that it is bent over andis not cleanly cut off.

SUMMARY OF THE INVENTION

[0004] According to the present invention there is provided an improvedcrop converging arrangement for a mower-conditioner equipped with arotary cutter bar.

[0005] An object of the invention is to provide a mower-conditionerhaving a rotary cutter bar with which a converging arrangement isassociated that includes driven converging drum sets located at oppositeend portions of the cutter bar, with each set being disposed generallyalong a line that diverges to the rear from the line of centers of thecutter disks towards the conditioner arrangement.

[0006] A more specific object of the invention is to provide amower-conditioner, as set forth in the immediately preceding object,wherein each driven converging drum set includes at an outer and aninner drum, with the outer drum being located on the rotation axis ofthe outer cutter disc, and with the inner drum being located inward fromthe outer drum and towards the rear a distance which results in itsouter periphery being to the rear of the line of centers of the cutterdiscs.

[0007] Another object of the invention is to provide amower-conditioner, as set forth in the immediately preceding object,wherein each converging drum set includes at least an outer and twoinner converging drums, with the inner two drums being driven by a driveshaft and gear arrangement that obtains its power from the drive thatpowers the crop conditioning arrangement.

[0008] Still a more specific object of the invention is to provide amower-conditioner, as set forth in the immediately preceding object,wherein the middle drum of each set is located slightly to the rear of aline of centers connecting the outer and inner drums.

[0009] Another object of the invention is to provide sets of convergingdrums, as set forth in one or more objects above, wherein a stripper isprovided for preventing recirculation of crop.

[0010] An alternative object of the invention is to provide amower-conditioner, as set forth in the first object stated above,wherein the inner two converging drums of each set are respectivelydriven at a selected speed by hydraulic motors.

[0011] These and other objects of the invention will become apparentfrom a reading of the ensuing description together with the appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a schematic left side elevational view of amower-conditioner platform, of the roll conditioner type, having a cropconverging drum arrangement constructed in accordance with the presentinvention and showing a portion of the drive for the cutter bar,conditioner rolls and converging drums.

[0013]FIG. 2 is a somewhat schematic top plan view of the left-handportion of the mower-conditioner platform showing the relationshipbetween the cutter bar and the left-hand set of converging drums.

[0014]FIG. 3 is a right front perspective view of the left end portionof the cutter bar with the left-hand set of converging drums.

[0015]FIG. 4 is a right rear perspective view of the drive arrangementlocated at the left end portion of the mower-conditioner platform fordriving the converging drum arrangement and the conditioner rolls.

[0016]FIG. 5 is a right rear perspective view of that portion of thedrive arrangement for driving the right-hand set of converging drums.

[0017]FIG. 6 is a left rear perspective view of an alternate drivearrangement embodiment showing the drive for a hydraulic pump formingpart of a hydrostatic drive for the inner pair of converging drums ofeach of the right and left-hand sets of converging drums.

[0018]FIG. 7 is a right side perspective view showing the hydraulicmotor of the alternate drive arrangement coupled for diving the innerpair of converging drums of the right-hand set of converging drums.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] Preliminarily, it is to be noted that while some structure may bestated as occurring in pairs, only one of the pair may be shown with itto be understood that the other of the pair is identical or a mirrorimage of the one shown.

[0020] Referring now to FIGS. 1 and 2, a part of a mower-conditionerheader or platform 10 is shown including a body defined by right-andleft-hand side walls, of which only the left-hand side wall 12 is shown.Left- and right-hand upright transverse walls or bulkheads 14 and 16(FIG. 7), respectively, extend inwardly from the side walls. The left-and right-hand bulkheads 14 and 16 respectively terminate inwardly atthe forward ends of left- and right-hand, upright, fore-and-aftextending inner side walls 18 (FIG. 2) and 20 (FIG. 7), respectively.The left- and right-hand inner side walls 18 and 20 define a cropdischarge passage 22 between them. While the bulkheads could be variousupright configurations without departing from the present invention,they are here shown as including respective vertical lower sections 24Land 24R, horizontal middle sections 26L and 26R, and vertical uppersections 28L and 28R.

[0021] An elongate rotary cutter bar 30 extends between the left-handside wall 12 and the right-hand side wall. Extending the length of, anddefining a rear portion of, the cutter bar 30 is a stiffener beam 32 ofsquare cross section that is bolted to lower portions of the pair oflower bulkhead sections 24L and 24R. While the present invention couldbe advantageously applied to rotary cutter bars of variousconstructions, the cutter bar 30 is a known type containing a pluralityof intermeshed spur gears (not shown), including idler and drive gearscoupled for effecting rotation of respective drive shafts of a pluralityof cutting units spaced along the length of the cutter bar 30. Fordetails of the cutter bar 30, reference may be had to U.S. Pat. No.5,012,635, issued to Walters et al. on May 7, 1991, which isincorporated herein, in its entirety, by reference.

[0022] Left-hand and right-hand sets of three cutting units arerespectively provided at the opposite ends of the cutter bar 30 witheach set including an end or outer cutting unit 34, a middle cuttingunit 36 and an inner cutting unit 38 all rotating so as to deliver cropmaterial towards the discharge passage 22 at the center of the platform.Accordingly, as viewed from the top, respective oval-shaped,blade-equipped cutting discs 40, 42 and 44 of the three cutting units atthe left-hand end of the cutter bar 30 all rotate clockwise, while thethree discs at the right-hand end of the cutter bar 30 rotatecounterclockwise. A roll-type crop conditioner 46 is mounted across thedischarge opening 22 for receiving crop delivered by the cutting unitsof the cutter bar 30, the conditioner 46 including lower and upperconditioner rolls 48 and 50, respectively. The rolls 48 and 50 could beof any desired construction for effecting crimping and/or crushing ofcrop stems, but are here shown as a type including a plurality oflongitudinal flutes welded to a cylindrical metal core (not shown)having circular plates welded at the interior of its opposite ends, withthe lower roll 48 having right- and left-hand stub shafts 52 fixed toand projecting outwardly from associated ones of the circular plates androtatably received in bearings mounted to the left- and right-hand innerwalls 18 and 20, and with the upper roll 50 having opposite endssimilarly provided with left- and right-hand stub shafts 54. Theright-hand stub shaft 52 of the lower conditioner roll 48 is rotatablyreceived in a bearing housing 56 (FIGS. 5 and 7) that is mounted to theright-hand inner side wall 20. The stub shafts 54 at the opposite endsof the upper conditioner roll 50 project through vertically elongatedopenings (not shown) provided in the inner side walls 18 and 20, and arerotatably received in respective bearings carried by housings mounted torespective arms (not shown) pivotally mounted to the walls 18 and 20 forpermitting the upper roll 50 to move toward and away from the lower roll48 in response to variations in the thickness of a mat of crop passingbetween the rolls 48 and 50. Springs (not shown) normally yieldably biasthe arms against downstops (not shown). The right-hand stub shaft 54 islocated in a bearing housing 58 (FIGS. 5 and 7).

[0023] A main power distribution gear box 60 includes a housing 62located vertically above the left-hand end cutting unit 34. A powershaft 64 extends vertically through the housing 62 and has an upperinput end coupled to a power source in the form of a reversiblehydraulic motor 66. The power shaft 64 is coupled, through right-anglegearing (not shown), for driving a horizontal, leftward extending outputshaft 68. A lower end of the power shaft 64 is connected, by a universalcoupler 70 (FIG. 3), with an inlet shaft, not visible, of the cuttingunit 34. This inlet shaft carries a gear which is coupled for rotatingthe end cutter disc 40 and is meshed for distributing power through aconstant mesh gear train that supplies power for rotating the remainingcutter discs of the cutter bar 30.

[0024] Fixed for rotation with the output shaft 68 is a multiple groovebelt pulley 72. Referring now also to FIG. 4, it can be seen thatmounted in approximate axial alignment with the upper conditioner rollstub shaft 54 is an upper shaft 74 which is mounted in, and projects tothe right from, a conditioner roll drive gear housing 76 mounted to aleft end portion of the bulkhead upright wall section 24L. An upper,telescopic drive shaft 78 has its opposite ends respectively universallycoupled to the shaft 74 and the left-hand stub shaft 54 of the uppercrop conditioning roll 50. Mounted to the shaft 74 in fore-and-aftalignment with the pulley 72 is a multiple groove v-belt pulley 80having two more grooves than the pulley 72. A banded v-belt 82 extendsbetween the pulleys 72 and 80. A lower shaft 84 is mounted in, andprojects to the right from, the gear housing 76 in general alignmentwith the left-hand stub shaft 52 of the lower conditioner roll 48. Alower drive shaft 86 has its opposite ends respectively universallycoupled to the lower shaft 84 and the left-hand stub shaft 52 of thelower conditioner roll 48. Located in the gear housing 76 andrespectively fixed to the upper and lower shafts 74 and 84 are upper andlower, constantly meshed spur gears 88 and 90.

[0025] As viewed in FIG. 1, the output shaft 68 of the powerdistribution gear box 60 rotates counterclockwise resulting in the upperconditioner roll 50 being likewise rotated counterclockwise. Thisrotation is in turn transferred through the gears 88 and 90 so as tocause the lower conditioner roll 48 to be rotated clockwise.

[0026] A double groove v-belt pulley 92 is mounted to the upper verticalsection 28L of the bulkhead 14 at a location aligned fore-and-aft with,and spaced upwardly and forwardly from the outer two grooves of thepulley 82. The pulley 92 is fixed to the left-hand end of a shaft 94that is journalled for rotation in a sleeve 96. A pair of v-belts 98extend about the pulleys 80 and 96 and are kept properly tensioned by anidler pulley 100 carried by an arm 102 that is biased downward by aspring assembly 104. Thus, it will be appreciated that the shaft 94 isdriven at a speed which has a direct relationship to the speed that thecutting discs and crop conditioning device are driven.

[0027] Provided for augmenting the rotating cutter discs in conveyingcut crop into the passage 22 for further processing by the conditionerrolls 48 and 50 are right and left-hand converging drum sets, with onlythe left-hand set 106 being shown. As can best be seen in FIGS. 2 and 3,the left-hand converging drum set 106 includes outer or end,intermediate and inner converging drums 108, 110 and 112, respectively.As can be seen in FIG. 2, the intermediate converging drum 110 is setback slightly from a line A which is tangent to a front location of theouter and inner converging drums 108 and 112 and also from a line ofcenters C passing through the axes of rotation of the outer andintermediate cutting discs 34 and 36, respectively. It has been foundthat this set back of the intermediate drum 110 results in better cropconvergence as this gives extra space for the cut crop coming off theouter cutting disc 34 so that the cut crop is not urged forward by therotating drum 110 to the extent that uncut crop is pushed down resultingin a streak of taller stubble than is left along the remainder of thecutter bar 30. It has been found that in some crop conditions and/orcutterbar lengths that only the drum 110 is needed for improving cropconvergence.

[0028] Each of the converging drums 108, 110 and 112 includes top andbottom, vertically spaced, circular plates 114 joined by four verticalangle members 116 spaced equal about the respective axes of rotation ofthe drums, it being noted that the lower plate 114 of the outer drum 108is fixed for rotation with the cutting disk 40. Closing the gaps betweenthe angle members 116 of each of the intermediate and inner convergingdrums 110 and 112 are respective plates 118, which each have avertically extending angle formed between opposite end portions that areengaged with and bolted to legs of the adjacent ones of the anglemembers 116. Thus, the drums 110 and 112 are completely enclosed, tolessen the tendency to grab and wrap crop, and provide eight corners foragressively engaging crop.

[0029] Further enhancement of the converging function is provided byright-and left-hand crop converging or guide shields respectivelyassociated with the right- and left-hand converging drum sets, with onlythe left-hand shield 120 being shown (see FIGS. 2 and 3). The guideshield 120 is in the form of a vertical sheet having, as can be seen inFIG. 2, a transverse outer section 122, extending inwardly from theouter side wall 12 in general tangential relationship to, andterminating at a front surface of the outer crop converging drum 108. Aninner section 124 is joined to, and angled inwardly and to the rearfrom, the outer section 122 to a location of the front vertical uppersection 28L of the bulkhead 14 that is spaced a short distance outwardfrom the inner side wall 18. The guide shield 120 has a substantiallyhorizontal lower edge 126 disposed at a height just below the tops ofthe converging drums 108, 110 and 112 so that the shield 120 acts tostrip crop tending to flow above the drums. Extending from the innerconverging drum 112 to the crop discharge passage 22 is a stripper plate128 having an outer edge disposed closely adjacent the outer peripheryof the inner converging drum 112 and a bottom edge engaged with the topof the cutter bar 30. The stripper plate 128 is mounted to the bulkheadsection 28L in a location free from the paths of rotation of the knivesof the cutter discs 42 and 44.

[0030] Referring now also to FIG. 4, it can be seen that vertical driveshafts 130 and 132 are respectively fixed to a central location of theupper circular plates 114 of the intermediate and inner drums 110 and112, the shafts 130 and 132 projecting upward through the horizontalsection 26L of the bulkhead 14. Mounted to the upper ends of the shafts130 and 132 are drive pulleys 134 and 136, respectively, that aretoothed and engaged by a toothed drive belt 138 extending about them.The drive belt 138 is kept properly tensioned by a toothed first idlerpulley 140 engaged with the inner or toothed side of the belt at alocation to the rear and left of the drive pulley 136. A second idlerpulley 142 has a smooth groove engaged with the outer or smooth side ofthe belt 138 at a location spaced slightly to the left and forward ofthe first idler pulley 140. Both of the idler pulleys 140 and 142 aremounted for rotating about upright shafts fixed to the horizontalsection 26L of the bulkhead 14, with the shaft of the pulley 142 beingadjustable along a fore-and-aft extending slot (not shown) provided inthe horizontal bulkhead section 26L.

[0031] Mounted to the upright bulkhead section 28L at a location spacedvertically above the drive shaft 132 is a gear box 144 through whichextends a horizontal drive shaft 146. Right angle gearing (not shown)couples the shaft 146 to an output shaft (not visible) having its lowerend coupled to the converging drum drive shaft 132 by a connecting shaft148 having universal couplers at its opposite ends. The right anglegearing is arranged so as to cause the converging drums 110 and 112 tobe driven clockwise, as viewed from the top in FIG. 2. Power istransferred from the pulley 92 to the gear box 144 by a telescopic powertransfer shaft 150 having its left- and right-hand ends respectivelycoupled to the shafts 94 and 146 by universal couplers.

[0032] Referring now to FIG. 5, there is shown the arrangement fordriving the intermediate and inner converging drums (not shown) of theleft-hand converging drum set. Specifically, a gear box 152, of aconstruction similar to that of the gear box 144, is mounted to thevertical section 28R of the bulkhead 16 at a location spaced verticallyabove a drive shaft (not visible) of an inner converging drum (notshown) of the right-hand converging drum set. A drive shaft 154 extendshorizontally through the gear box 152 and right angle gearing (notshown) is arranged for transferring power from the shaft 154 to avertical output shaft 156 so as to cause the latter to be rotatedcounterclockwise, as viewed from the top. A connecting shaft 158, havinguniversal couplers at its opposite ends, is coupled between the outputshaft 156 and the drive shaft (not visible) of the inner convergingdrum. Respectively mounted to the drive shafts of the inner andintermediate converging drums are cog drive pulleys 160 and 162. A cogdrive belt 164 extends about, and is engaged with, the teeth of thepulleys 160 and 162, and is maintained in proper tension by a toothed,first idler pulley 166 mounted for rotation about a shaft fixed to thebulkhead horizontal section 26R at a location spaced to the right and tothe rear of the drive pulley 160. A second idler pulley 168 is mountedfor rotation about a shaft located in a fore-and-aft adjustment slot 169(see FIG. 7) provided in the bulkhead section 26R at a location just tothe right and forward of the idler pulley 166. A power transfer shaft(not shown) having universal couplers at its opposite ends is coupledbetween the right-hand end of the shaft 146 located in the gear box 144(FIG. 4) and the left-hand end of the shaft 154 located in the gear box152.

[0033] The operation of the embodiment thus far described is statedbelow. Normal cutting operation of the platform 10 is initiated bycontrolling the motor 66 such that its output shaft rotates in aforward, clockwise direction, as viewed from the top, resulting inclockwise rotation of the outer cutter disc 40. The gear train containedin the cutter bar 30 is arranged in a well known manner so as to resultin the cutter discs 42 and 44 being driven so that they also rotateclockwise and so as to drive the outer three cutter discs on theleft-hand end portion of the cutter bar 30 such that they rotatecounterclockwise, whereby cut crop is delivered towards the rollconditioner 46 located in the crop discharge passage 22 at the center ofthe platform 10.

[0034] This centering of the cut crop is aided by the right- andleft-hand converging drum sets in conjunction with the right- andleft-hand converging or guide shields. Specifically, with respect to theleft-hand converging drum set 106 and shield 120, the outer drum 108 isdriven clockwise with the cutting disc 40 while the intermediate andinner drums 110 and 112 are driven clockwise through operation of thedrive which, as can be seen in FIGS. 1 and 4, includes the belt 82 thattransfers power from the main power distribution gear box 60 to theinput shaft of the conditioner roll drive gear housing 76 and the pairof belts 98 which transfer power to the shaft 94 that is, in turn,coupled to the shaft 146 of the gear box 144 that is connected fordriving the inner converging drum 112, the shaft 146 being coupled tothe shaft 154 of the gear box 152 that is coupled for driving the innerconverging drum of the left-hand converging drum set (not shown). Thetoothed or cog drive belts 138 and 164 are respectively coupled fordriving the intermediate converging drum 110 of the left-hand convergingdrum set 106 and the intermediate drum of the right-hand converging drumset. Thus, it will be appreciated that the sets of converging drums aredriven at a speed which is related to the speed at which the cuttingdiscs and conditioning rolls 48 and 50 are driven.

[0035] With respect to the left-hand converging drum set 106, the heightof the converging drums 108, 110 and 112 cooperate with the set back ofthe intermediate drum 110 from the tangent line A to cause the cut cropto flow to the discharge opening 22 without bunching to the extent thatit causes uncut crop to be pushed down and cut such as to leave a streakof taller stubble than would occur if the crop had not been pushed down.Further, crop is kept out of the zone behind the converging drum set 106by the cooperative stripping action of the lower portion of theconverging shield 120, which prevents crop from going over the tops ofthe converging drums, and the stripper plate 128, which strips crop fromthe inner converging drum 112. Of course, the right-hand converging drumset and converging shield operate in a similar fashion.

[0036] An alternative to the drive arrangement for directly driving theinner and intermediate drums of each of the right-and left-handconverging drum sets is disclosed in FIGS. 6, 7 and 8, wherecollectively, there is shown a hydraulic drive system. Specifically,referring now to FIG. 6, it can be seen that the drive belt 82 isengaged with a pulley 80′ having only a single v-groove at its innerend. A fixed displacement hydraulic pump 170 is mounted at a heightabove, and has a pulley 172 located in alignment with, the v-groove ofthe pulley 80′. A v-belt 174 transfers the rotation of the pulley 80′ tothe pump 170. Referring now also to FIGS. 7 and 8, it can be seen thatthe pump 170 includes an inlet port coupled to a reservoir 176 by aconduit 178, and an outlet port coupled to an inlet of a control valve180 by a conduit 181. The control valve 180 is a metering valve, whichmay be of any remotely controllable type. The valve 180 has a bypassport coupled to the sump 176 by a branched return conduit 182 and a workport coupled to a first fixed displacement motor 184 by a supply conduit186. The first motor 184 is coupled in series with a second fixeddisplacement motor 188 and, thus, has its outlet coupled to the inlet ofthe motor 188 by a conduit 190, the outlet of the second motor 188 beingcoupled to the reservoir 176 by the return conduit 182. The speed of themotors 184 and 188 may be selected by operation of the valve 180. InFIG. 7, it can be seen that the second motor 188 is mounted directly tothe toothed pulley 160 of the drive for the intermediate and innerconverging drums of the right-hand converging drum set. The first motor184 would similarly be mounted to the pulley 136 of the drive for theintermediate and inner converging drums of the left-hand converging drumset 106. A toothed plate 190 is used as part of the structure couplingthe motor 188 to the pulley 160, and an electrical or electromagneticspeed sensor (not shown) may be disposed such that, as the teeth of theplate 190 rotate past it, electrical pulses occur which are convertedand sent to a speed indicator located for viewing by an operator so thathe may adjust the control valve 180, if necessary, to obtain a desiredspeed of operation.

1. In a crop harvesting platform including opposite, fore-and-aftextending side walls, a transverse rotary cutter bar extending betweensaid side walls and equipped with a plurality of rotary cutting unitsincluding at least right- and left-hand end and second cutting unitsoperating together for delivering crop to a centrally located dischargezone between said right- and left-hand second cutting units, and right-and left-hand outer crop converging drums respectively being mounted forrotation with said right- and left-hand end cutting units, theimprovement comprising: at least a second crop converging drum beingmounted between each outer crop converging drum and said dischargepassage, with said second crop converging drum being located inward andto the rear of said outer crop converging drum.
 2. The crop harvestingplatform as defined in claim 1 wherein said second crop converging drumhas an outer periphery which is located to the rear of a line of centerspassing through respective axes of rotation of said right- and left-handend and second cutting units.
 3. The crop harvesting platform as definedin claim 1 wherein a third crop converging drum is mounted between eachouter crop converging drum and said discharge zone for rotation aboutrespective upright axes, with each third crop converging drum beingrespectively located inward and to the rear of the adjacent second cropconverging drum; and a drive arrangement for driving adjacent ones ofsaid second and third crop converging drums in a direction of rotationfor conveying crop toward said crop discharge zone.
 4. The cropharvesting platform defined in claim 3 wherein said end, second andthird converging drums at each side of the platform are substantiallyequal in diameter; and said second converging drum being spaced to therear from a line that is tangent to a forward location of said outer andthird converging drums.
 5. The crop harvesting platform defined in claim1 wherein said discharge zone is defined by a pair of spaced apart innerside walls; a roll conditioner assembly extending between said pair ofinner side walls and including lower and upper conditioner rollsdefining a crop receiving nip between them; and said converging drumshaving a height which is above that of said nip.
 6. The crop harvestingplatform defined in claim 3 and further including an upright cropconverging shield at each side of said platform that extends inward fromthe adjacent side wall so as to pass close to the forward side of eachof said end, second and third converging drums closest to said adjacentside wall; and each converging shield having a substantially horizontalbottom edge disposed at a level just below that of the tops of theadjacent converging drums so that the converging shields act to stripcrop so that it does not pass over the tops of the converging drums. 7.The crop harvesting platform as defined in claim 3 wherein an uprightcrop stripping plate extending between each of said third convergingdrums and said discharge zone for preventing crop from being conveyedbehind said converging drums.
 8. In a crop harvesting platform includingopposite, fore-and-aft extending side walls, a transverse rotary cutterbar extending between said side walls and equipped with a plurality ofrotary cutting units including at least right- and left-hand end andsecond cutting units operating together for delivering crop to acentrally located discharge passage defined between right- and left-handinner side walls, a crop conditioner arrangement mounted across saiddischarge passage, right- and left-hand end crop converging drumsrespectively being mounted for rotation with said right- and left-handend cutting units, and a platform drive arrangement including a powerdistributing main gear box having drive distribution components coupledfor receiving power from a power source and delivering it to one of saidend cutting units and to a power transfer arrangement; the improvementcomprising: second and third converging drums mounted on each side ofsaid platform between said end converging drum and said dischargepassage and including respective upright, second and third convergingdrum drive shafts; first and second converging drum drive pulleysrespectively being coupled to said second and third converging drumdrive shafts at each side of said platform; and said power transferarrangement including power transfer components coupled for driving saidconditioner arrangement and for driving each of said third convergingdrum drive shafts.
 9. The crop harvesting platform defined in claim 8wherein said power transfer components include first and second beltpulleys respectively mounted on first and second parallel, transversestub shafts; a belt arrangement trained about said first and second beltpulleys; a conditioner drive shaft being coupled to said first stubshaft; and a converging drum drive shaft being coupled to said first andsecond stub shafts.
 10. The crop harvesting platform as defined in claim8 wherein said power transfer components include first and second beltpulleys respectively mounted on first and second parallel, transversestub shafts; a belt arrangement trained about said first and second beltpulleys; a conditioner drive shaft being coupled to said first stubshaft; said second stub shaft forming an input shaft of a hydraulicpump; and first and second hydraulic motors being respectively mountedfor driving said third converging drum shafts at the opposite sides ofsaid platform and being hydraulically coupled for receiving workingfluid from said hydraulic pump.
 11. The crop harvesting platform asdefined in claim 10 and further including a control element forselectively controlling the speed of said motors whereby the speed ofoperation of said second and third converging drums at each side of saidplatform may be selected.
 12. A converging drum for use with a cropharvesting platform, comprising: first and second horizontal, verticallyspaced circular plates centered on an axis of rotation of said drum; aplurality of angle members extending between and having opposite endsrespectively fixed to said upper and lower circular plates at locationsspaced equally about said axis; each angle member having a pair of legsdiverging from a corner extending between peripheral locations of, andopening toward said rotational axis of, said first and second circularplates; a gap being defined between adjacent legs of adjacent anglemembers; a gap-filling plate member being located in each gap and havinga pair of opposite, upright marginal portions overlapping, and beingsecured to, said adjacent legs of adjacent angle members; and each platemember being formed so as to define an angular portion located halfwaybetween said opposite upright marginal portions so as to define a cornerwhich extends parallel to and is halfway between the corners of adjacentones of said angle members, the plate members thus cooperating with saidangle members and circular plates to define an enclosure which reducesthe tendency for crop to get caught by and wrap about the convergingdrum.
 13. The converging drum as defined in claim 12 wherein theconverging drum includes at least four angle members and four platemembers so that the corners of these members define eight crop engagingribs.
 14. The converging drum as defined in claim 12 wherein said legsof said angle members meet so as to form a right angle corner.